Wagner M, Bielby S, Rennie I G, Mac Neil S
University Department of Medicine, University of Sheffield, Northern General Hospital, UK.
Melanoma Res. 1997 Dec;7(6):439-48. doi: 10.1097/00008390-199712000-00001.
The purpose of this study was to examine which intracellular signalling systems influence the attachment of normal uveal melanocytes and uveal melanoma cells to extracellular matrix (ECM) proteins in vitro. Uveal melanocytes were found to attach strongly to fibronectin in preference to plastic, collagens type I, III or IV, or laminin. In contrast, uveal melanoma cells attached equally well to fibronectin and collagens I, III and IV in preference to plastic or laminin. Manipulation of intracellular cyclic AMP or protein kinase C had little, if any, effect on the attachment of either cell to fibronectin. In contrast, inhibition of calmodulin significantly inhibited the attachment of both normal and transformed cells, as did manipulating intracellular free calcium. We noted that the intracellular free calcium in melanoma cells was less than half that seen in melanocytes. Fibronectin, laminin and Arg-Gly-Asp (RGD) were all capable of acutely increasing the intracellular free calcium in both cells. ECM-induced increases in calcium were more apparent in low density than high density cells and appeared more sustained in melanocytes than in melanoma cells. We conclude that both normal and neoplastic uveal melanocytes require an intracellular signal or signals which involves calcium and calmodulin in the few minutes following cell binding to ECM proteins in order for successful cell attachment to occur. While the transformed cell does not differ significantly from the normal cell in this respect, this dependency on calcium and calmodulin may nevertheless offer an approach for pharmacological intervention in the prevention or arrest of metastatic spread and merits further investigation.
本研究的目的是检测哪些细胞内信号系统在体外影响正常葡萄膜黑素细胞和葡萄膜黑色素瘤细胞与细胞外基质（ECM）蛋白的附着。研究发现，葡萄膜黑素细胞优先强烈附着于纤连蛋白，而非塑料、I型、III型或IV型胶原蛋白或层粘连蛋白。相比之下，葡萄膜黑色素瘤细胞对纤连蛋白以及I型、III型和IV型胶原蛋白的附着情况相同，且优先于塑料或层粘连蛋白。细胞内环磷酸腺苷（cAMP）或蛋白激酶C的调控对两种细胞与纤连蛋白的附着几乎没有影响（如果有影响的话）。相反，钙调蛋白的抑制显著抑制了正常细胞和转化细胞的附着，调节细胞内游离钙也有同样效果。我们注意到，黑色素瘤细胞内的游离钙不到黑素细胞的一半。纤连蛋白、层粘连蛋白和精氨酸-甘氨酸-天冬氨酸（RGD）均能迅速增加两种细胞内的游离钙。细胞外基质诱导的钙增加在低密度细胞中比在高密度细胞中更明显，且在黑素细胞中比在黑色素瘤细胞中更持久。我们得出结论，正常和肿瘤性葡萄膜黑素细胞在细胞与细胞外基质蛋白结合后的几分钟内都需要一种或多种涉及钙和钙调蛋白的细胞内信号，以便成功发生细胞附着。虽然在这方面转化细胞与正常细胞没有显著差异，但这种对钙和钙调蛋白的依赖性仍可能为预防或阻止转移扩散的药物干预提供一种方法，值得进一步研究。
